Tom Swift and His Airship

"Are you all ready, Tom?"
"All ready, Mr. Sharp," replied a young man, who was stationed near some complicated apparatus, while the questioner, a dark man, with a nervous manner, leaned over a large tank.
"I'm going to turn on the gas now," went on the man. "Look out for yourself. I'm not sure what may happen."
"Neither am I, but I'm ready for it. If it does explode it can't do much damage."
"Oh, I hope it doesn't explode. We've had so much trouble with the airship, I trust nothing goes wro...